Swivel-caster.



J. L. CHESNUTT. SWIVEL CASTER.

. APPLlcAnoN FILED Aua.1. |914.

Patented June v15, 1915.

JOHN 7. ovczfnr CHEsNz/rr w JOHN LOUCIEN CHESNUTT, OF KANSAS CITY, MISSOURI.l

SWIVEL-CASTER.

Speoiicationvof Letters Patent.

Applicationled August 7, 1914. Serial No. 855,937.

' ing is a specification.

The object of this invention is to provide an improved construction for a ball-bearmg swivel caster.

A further object of this invention is to provide an improved construction whereby a caster wheel may be employed havlng a maximum diameter relative to the height of the caster, the caster being located directly beneath the load.

A further object `of this invention 1s to provide means for dispensing with the center' rivet in a swivel caster, thereby facilitating swiveling chiefly by preventing blnding and friction between the contacting surfaces of the wheel bearing part and the attachingplate. l

A further object of this invention is to provide .an improved construction for a swivel caster having two horizontal rings of bearing balls,

ring being designed to take the lateral pressure of the load. f l

y My invention consists in the construction, arrangement and combination of elements hereinafter set forth, pointed out in my claims and illustrated by the accompanying Vdrawing,.in which-' 4Figure 1 is a plan of my improved caster, a part of the hidden construction being in; dicated by dotted lines. elevation and Fig. 3 a side elevation of the same, 'each of said views being shown partly in section. Fig. 4 is a front elevation of a modified form of my invention, partly in therefrom, said base or bottom being formed with a central, longitudinal rectangular` opening 12; and spaced flanges 13, 14 depending from said base or bottom at the side -5'5 margins of said opening. A Wheel 15 is the upper ring being designed?, to take the downward pressure and the lower Fig. 2 1s al front' "to the outer frame member 11. This mounted within the tom and the axle 16 thereof is carried in the flanges 13, 14. The axle mounted in such position that the wheel 15 is somewhat back of the longitudinal center of the opening 12 and of the ring 10. The wheel 15 is of such diameter as to extend upwardly entirely through andpreferably project slightly the ring 10. An ring 17 mounted of and concentric outer frame is formed cfa in upright position outside with the ring 10, and a plate ring 10.. The spaced, apertured lugs 19 by which it is secured to the plate 18 by means of screws or rivets 20 having their heads countersunkin said plate. The plate 18 is formed with a circular opening 2l in its center to receive the upper portion of the wheel 15. The plate 18 is formed with screw holes 22 by which the device may be attached to any desired load such as a truck, article of fur? niture or the like. The inner ring 10 is formed 'with an outwardly projecting, peripheral annular rib or fiange 23 intermediate of the upper and lower margins of said ring, and projecting toward but spaced raten-tea .rune '15, 1915.

opening 12 Aof the bot- 16 preferably is above the upper plane of` l 18 mounted on said ring and voverlying the plate 17 is formed with at its outer circumference from the outer l ring 17. An upper row 'of bearing balls 24 is mounted between the plate 18 and annular vflange 23 and between the rings `10 and 17. The balls 24 rest on the flange 23 and are 'contactedby the plate 18, thus bearingand A lower ring of- 26 and are contacted` by the rings10 and 17,

the inner frame relative and eliminatin the friction from contact thereof; but sai balls are not contacted normally by' the flange 23, thusieliminating al1 downward pressure and friction on said balls. y Y

' I prefer to construct the inner frame with thereby centering a reinforcement 27 at the front and rear of e wheel 15, between. the ring .10 andbase reiiforcement preferably is beveled, as at 27, a the forward and rear uro f margins of the opening 12, to correspond approximately to the curvature of the wheel 15..

Particular attention is-called to the fact that the use of the double ring of bearing balls and the elimination of the center rivet commonly employed in swivel casters per-` mits a free and easy swivel or turn of the inner or wheel-.bearing frame relative to the outer or load-bearing frame. Any tendency to tip, caused by the passing over an uneven surface, is counteracted by the lower balls 25, which are then contacted by the lower side of the annular flange 23. The setting of the wheel back of the center of the device also facilitates the swivel turn; but in my improvement, owing to the freedom from binding and friction between the wheel bearing part and the attaching plate, it is not necessary to set the wheel so far back of center in order to induce swiveling; further eliminating the binding and friction between said parts due to the tendency to tip. lt is well known that in a caster containing a center rivet there is a constant binding and friction between the parts at the point where they are held together by the rivet. i This binding is due to the tend-` ency of these two parts Aof the caster to separate at the rivet, and forward therefrom in frontof the caster wheel. Such tendency to separate is due to the caster wheel being.

axled, considerably behind the center in order to compelait to swivel with certainty, and thisinduces a leverage that causes constant. binding as above stated. This tendency to separate, or tip, is especially pronounced durin'g progressive movement of the caster under load, and greatly hinders the swiveling action of the caster. ln my construction, the elimination of the center rivet prevents binding during such tendency to tip laterally or forwardly. Great advantage is derived ing a Wheel of approximately the same diameter as the height of the caster, inthat a large wheel runs more easily and is less hampered by running into obstructions or over uneven surfaces.. This advantage is attained, in this device, in a caster adapted to be mounted directly beneath the load. l

ln the construction according to'Fig. 4,

substantially the same elements as those.

above described are present, except that the lower ring of balls 25 is omitted and tipping of the device is prevented by contact lof the flanges 23a and 26, between which there is a slight space and no contact except during strong tendency to tip, as when" the wheel is going over a very rough surface.I ln this construction also l have shown the balls 24 placed at a lower level relative to the axle 16, and the wheel 15 precting throu h and materially above the plate 18. lt 1s esirable to set the load as low as posa periphe thus from employ-` y ing myself to the inmenso sible relative to the axle in order to prevent the tendency to tip. lt is often desirable also to place the attaching plate as low as possible in relation to the height of the caster wheel in order not to increase the height of the load unduly above the floor. In this construction the ring 10a is foreshortened as to height and the member l1a has less cncavity than in the other construction.

ln the construction according to Fig. 5 the inner tif/rame is formed as a disk 11b with al flange 28b at its base, and the Hange of tie ring 17a is omitted.` The outer periphery of the disk 11b and the inner periphery of the ring 17a are slightly concaved to form coacting membersof a race containing a ring of balls 24. The top member 18a of the outer ring preferably is formed integral with the ring 17. The balls 24are inserted into the race through a hole formed in, the ring 17a, which hole is then closed by a screw 2S having its inner end flush with the inner surface of said ring. The flanges of the inner frame, one of which is shown in the drawing .and designated by the numeral 13a, project upwardly through the opening 21, so that the axle 16 is carried above the plane of the balls'24. The axle 16 preferably is carried by special bearers 29 of angle form adapted to be mounted in the inner frame from below, with the wheel and axle, and be secured as by screw 30. The .tendency to tip is wholly overcome by having the load attached on a plane below the plane of the axle, or. very near thereto. The inner frame is held in place by contact of the balls 24 with the concaved surfaces of the inner and outer frame.

lt is to be understood that the modifications shown are merely suggestions as to the various constructions which might be employed, especially with respect to the altitude of the bearing balls, tion of the load, relative to the axle.

l do not desire to be understood as limitprecise construction and arrangement herein shown and described, as various modications may be employed Without departing from the spirit of my 'invention. y

l claim as my invention- 1. A swivel caster, comprising an outer or load-bearing frame, an inner frame mounted within said outer frame, a wheel journaled for rotation in said inner frame and extending to the top thereof, and bearing balls between said inner and outer frames, said Wheel also extendingabove the plane of said bearing balls,

',2. A swivel caster, comprisingan outer frame formed with a removable top plate,

an inner frame therein, a wheel journaledlill@ lil@ said inner and outer frames, one row of said balls adapted to receive vertical friction only and the other row of said balls adapted normally to receive lateral friction only, said balls and their races forming the only connection between said inner and outer frames.

3.A swivel caster, comprising an outer frame formed with an inwardly projecting annular flange at its base, an -inner frame within said outer frame and formed with an outwardly projecting annular flange above the flange of the outer frame, a wheel journaled in said inner frame, a removable plate on the top of said outer frame, and bearing balls between said plate anjd the flange of the inner frame. 2,-.

4. A swivel caster, comprising an I"outer frame formed with an inwardly projecting flange at its base, an inner frame therein and formed with an outwardly vprojecting flange above the flange of the outer fra1ne, a wheel journaled in said inner frame, a removable plate on the4 top of' said outer frame, bearing balls between said plate and the flange of the inner frame, and bearing balls Ibetween the flanges of the two frames.

5. A swivel caster, comprising an outer frame formed with anv inwardly projecting flange at its base, an inner frame therein and formed with an outwardly projecting Harige above the flange of the outer frame, a wheel journaled in said inner frame, a removable plate on the top of said outer frame, and bearing balls between said plate and the flange of the inner frame, said plate, flanges and bearing balls forming the only connection between the inner frames. 6. A swivelcaster,

and outer first flange, said inner ring also being j formed with a concaved base member, said base member being formed with a longitudinal opening, flanges projecting downwardly from said base member at the side margins of said opening, a wheel mounted in said opening and having its aXle carried by said downwardly projecting flanges, bearing balls between said inner and outer rings, and a removable plate mounted on the top of said outer ring.

7. A swivel caster, comprising an outer frame formed -with a ball race, an'inner frame formed with a ball race coacting with the first ball race, bearing balls in said races, said inner frame being formed with a longitudinal opening, vertical flanges on said inner frame at side margins of said opening, and a wheel journaled for rotation in said opening and carried by said vertical flanges, said wheel extending above the plane of said bearing balls.

Signed by me at Kansas City, Missouri, this thirtieth day of J une, 1914. 

